A soft, supple and flexible skin has a marked cosmetic appeal and is an attribute of normal functioning epidermis.
As human skin ages with advancing years, the epidermis can become folded or ridged or furrowed to form wrinkles which signal the loss of youthful appearance and herald the transition to old age. This transition can occur prematurely with young people, especially those who expose themselves to excessive doses of sunlight. Also, the outer layer of the epidermis, that is the stratum corneum, can become dry and flaky following exposure to cold weather, or excessive contact with detergents or solvents which result in loss of skin moisture with the result that the skin loses its soft, supple and flexible characteristics.
Emollients such as fats, phospholipids and sterols have in the past been used to soften wrinkled or dry skin, but it is apparent that these emollients are only partially effective as a remedy for skin in poor condition.
Various other substances have been applied to skin and/or hair to confer various benefits.
Frequently an agent intended to confer a benefit for skin and/or hair constitutes only part of a product. Other material makes up the balance of the product and provides a carrier or vehicle for the active agent which is to be delivered to skin and/or hair. Products for application to skin and/or hair frequently take the form of emulsions which can be oil-in-water or water-in-oil emulsions. There have been various proposals of water-in-silicone oil emulsions.
US-A-4122029 (Dow Corning) teaches the formation of such emulsions with incorporation of a non-silicon emulsifier. US-A-4311695 (Dow Corning) teaches formation of such emulsions with a water and alcohol solution as the disperse phase and with an oil or fat included in the continuous phase. The suggested alcohols include ethanol, isopropanol, propylene glycol and glycerol but not polyhydric alcohols with 4 to 8 carbon atoms.
EP-A-271925 (Dow Corning) discloses water-in-silicone oil emulsions which are used as the base for cosmetic products such as eye shadow which include coloured pigment. EP-A-281394 (Richardson-Vicks) describes water-in-oil emulsions where the disperse phase is itself an oil-in-water emulsion. GB-A-2206048 (Boots) discloses water in silicone oil emulsions which spontaneously separate on standing but can be re-emulsified by shaking.
The documents referred to above use a volatile methyl siloxane fluid and a polydiorganosiloxane polyoxyalkylene copolymer.
It has also been proposed in EP-A-0 150 914 (Unilever) to provide a water-in-silicone oil emulsion containing an alkyl lactate and a silicone oil ingredient comprising a dispersion in a volatile siloxane of a polymer of dimethyl polysiloxane with polyoxyethylene and/or polyoxypropylene side chains, together with a nonionic liquid emulsifier having an HLB value of from 1 to 7, and a lower alkanol.
GB-A-2079300 (General Electric Company) discloses silicone oil-in-water emulsions containing non-silicon emulsifiers which are rendered transparent by incorporation of polyols.
The use of 2-hydroxyalkanoic acids for enhancing the quality of human skin following topical application thereto has already been described.
Thus, EP-A 0 007 785 (Unilever) discloses skin treatment compositions incorporating .alpha.-hydroxycaproic acid or .alpha.-hydroxycaprylic or mixtures thereof, the compositions having a pH value of less than 7, usually from pH values of from 2 to 4.
It is also proposed in US-A-4 105 782 (Yu & Van Scott) to use amines or ammonium salts of .alpha.-hydroxyacids in the treatment of acne or dandruff and, in the Yu & Van Scott patents U.S. Pat. No. 4,105,783 and U.S. Pat. No. 4,197,316, to use such compounds in the treatment of dry skin. U.S. Pat. No. 4,234,599 (Yu & Van Scott) discloses the use of .alpha.-hydroxyacids, and their esters or amine salts in the treatment of keratoses. In U.S. Pat. No. 4,363,815 (Yu & Van Scott) it is proposed to use .alpha.-hydroxyacids or .beta.-hydroxyacids or keto acids or their derivatives, in a composition for treating skin conditions.
According to GB 1 471 679, (Avon) it is known to use alkali metal salts of C.sub.2 -C.sub.5 .alpha.-hydroxycarboxylic acids in moisturising compositions.
In DE 2 110 993, (Henkel) there are disclosed alkali metal salts C.sub.4 -C.sub.10 .alpha.-hydroxycarboxylic acids, and the sodium salt of .alpha.-hydroxycaprylic acid is mentioned.